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Kaiser Foundation Health Plan

Disclosed Apr 12, 20242 years ago13,400,000 affectedConfirmed

Official notice

The covered entity (CE), Kaiser Foundation Health Plan, Inc., reported that it disclosed the protected health information (PHI) for up to 13,134,908 individuals while using third-party tracking technologies. The PHI involved clinical, demographic, and financial information. The CE notified HHS, affected individuals, and the media. In response to the breach, the CE: removed all third-party tracking technologies from its authenticated online platforms, trained or retrained workforce members, and implemented additional administrative safeguards.

What is known

People affected13,400,000 (as reported to HHS)
DisclosedApr 12, 2024
DiscoveredMay 31, 2023
HappenedMay 31, 2023
AttackRansomware
Data exposedNames, Health
SectorHealthcare · US
StatusConfirmed

Sources

Source
California Attorney General breach notice: Kaiser Foundation Health Planoag.ca.gov · Official notice
Washington Attorney General breach notice: Kaiser Foundation Health Planatg.wa.gov · Official notice
Oregon DOJ breach notice: Kaiser Foundation Health Planjustice.oregon.gov · Official notice
HHS OCR breach report (archive, resolved): Kaiser Foundation Health Plan (Health Plan, CA)ocrportal.hhs.gov · Official notice

Notices filed

WhereFiledPeople
California AGresidents of CAApr 12, 2024
Oregon DOJresidents of ORApr 12, 202413,400,000
HHS archivetotalApr 12, 202413,400,000
Washington AGresidents of WAJun 3, 202417,530

Other breaches at Kaiser Foundation Health Plan

BreachAffected
Disclosed Apr 6, 2022Apr 6, 20224 years agoInsider695
Disclosed Nov 7, 2019Nov 7, 20196 years agoInsider515
Disclosed Aug 31, 2017Aug 31, 20179 years agoInsider4,389
Disclosed Apr 22, 2016Apr 22, 201610 years agoLost or stolen device2,451
Disclosed Sep 11, 2013Sep 11, 201313 years agoUnknown
Disclosed Mar 16, 2012Mar 16, 201214 years agoUnknown
History of this record
  • 2026-09-25 · data_types: [] to ["names","health"] · backfill source
  • 2026-09-25 · records_basis: empty to hhs · backfill source
  • 2026-09-25 · records: empty to 13400000 · backfill source
  • 2026-09-25 · summary: empty to The covered entity (CE), Kaiser Foundation Health Plan, Inc., reported that it disclosed the protected health information (PHI) for up to 13,134,908 individuals while using third-party tracking technologies. The PHI involved clinical, demog · backfill source
  • 2026-09-25 · attack: unknown to ransomware · backfill source
  • 2026-09-25 · discovered: empty to 2023-05-31 · backfill source
  • 2026-09-25 · occurred: empty to 2023-05-31 · backfill source
  • 2026-09-25 · added · backfill source

First seen 2026-09-25 (California AG), confirmed by California AG. Record counts are as reported. Not legal advice.

Everything about Kaiser Foundation Health Plan

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